Digital cameras consume battery power at a very fast rate. Especially Alkaline batteries do not last very long in digicams. Newer types have been improved but only by about 30%. The reason is that alkaline batteries are intended to deliver their full capacity if the power is used slowly. Since digicams place a constant high power drain on batteries, lithium batteries are much more suitable but they are expensive and not rechargeable.
Do not confuse the Lithium batteries mentioned above with the rechargeable Lithium-Ion batteries. Another choice would be to use rechargeable NiMhs or NiCds in high drain applications such as digicams. A disadvantage of NiMhs, is that - if not used for some time - they will discharge by about 40% per month. Storing them in a cold place like a fridge or freezer, will lessen this effect, but keep them in a tightly sealed bag or container so they will stay dry, and let them adjust to room temperature before using them.
The one feature on a digicam that drains the most battery power is the LCD. This feature, which lets you preview images or set different camera functions, accounts for most of the power used. Switching it off while taking pictures will let you capture up to 5 times more images on a single charge. Only use it for reviewing images later to extend battery life.